The present invention relates to a device to measure the flow of fluids containing electrical charges and which has (1) an essentially horizontal pipe section in which the fluid flows and which is at least electrically insulating on its inner side, (2) a magnet arrangement which generates a magnetic field essentially diametrically in the pipe section, (3) an electrode arrangement which responds to a shift of the charges in the fluid which flows perpendicularly through the magnetic field, and (4) an evaluation circuit controlled by the electrode arrangement which produces an output signal corresponding to the fluid flowrate and which also takes into account the level of the fluid.
Devices of this kind are known from German Patent Applications P 31 26 965 and P 40 10 727 and from the European Patent Application 90 106 783.